Hydrocynus
| Hydrocynus | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
All five species of the genus Hydrocynus . From top to bottom: Hydrocynus vittatus, Hydrocynus tanzaniae, Hydrocynus forskahlii, Hydrocynus brevis, Hydrocynus goliath |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Hydrocynus | ||||||||||||
| Cuvier , 1816 |
Hydrocynus is a genus of fish from the African tetra family (Alestidae). The fish live in fresh waters of tropical Africa from Senegal in the west to the Nile in the north, Lake Turkana , Lake Albert and Lake Tanganyika in the east and the Okavango , Zambezi and Limpopo in the south.
features
Hydrocynus species have an elongated, silvery body, are 25 to 133 cm long and can weigh a maximum of 50 kg. Each individual scale is marked with a dark spot, so that parallel longitudinal stripes are created, which are only clearly visible above the side line . The intensity of these longitudinal stripes varies from species to species. The dorsal fin begins above or in front of the pelvic fin attachment . Both jaws are covered with a single row of very strong teeth that have a cutting function and are partially visible even when the mouth is closed. The tooth formula is 9–14 / 8–12, 12–20 / 8–14 for Hydrocynus goliath . The eyes can be almost completely covered by a nictitating membrane. The swim bladder does not extend behind the anus into the tail fin stalk. There are no external gender differences.
- Fin formula : dorsal 2 / 2–8, anal 3 / 11–14.
Way of life
Hydrocynus species live as predatory fish in lakes and rivers in the middle and upper water layers. Some areas and species are believed to also attack people in the water.
species
A total of five species belong to the genus Hydrocynus , which are difficult to distinguish from one another.
- Hydrocynus brevis (Günther, 1864)
- Hydrocynus forskahlii (Cuvier, 1819)
- Hydrocynus goliath (Boulenger, 1898)
- Hydrocynus tanzaniae Brewster, 1986
- Hydrocynus vittatus Castelnau, 1861
literature
- Melanie Stiassny, Guy Teugels & Carl D. Hopkins: The Fresh and Brackish Water Fishes of Lower Guinea, West-Central Africa, Volume 1. ISBN 9789074752206
Web links
- Hydrocynus on Fishbase.org (English)